Most of the time you can actually find older versions of apps in your recycle bin/Trash on your Desktop. Just delete the newer version in iTunes and I think you can drag and drop the older .ipa file into iTunes.
It's available on other repos too but that is the only one I have found with the updated version (0.0.5-2)
Basically, it will have a small popup show up in Pandora each time a song is played. You can have it set to download everything or individually (configure in the settings app). On the prompt all you need to do is tap to download into itunes library or swipe to dismiss. I have only barely messed with it but so far it seems like it works great. Love that it goes directly into the music app.